Problems have turned up after the coating phase in different fiber lines used for instance at the manufacture of cables. In fiber coloring lines and also band fiber lines and drawing towers, for instance, it has been necessary to clean all the used nozzle units inconveniently by hand after spreading acrylate. The cleaning has taken place by detaching the used nozzle units after each drive, by disassembling them and by cleaning the parts separately and by reassembling the units and by mounting them back in place in the line for next coating phase. Such an operation is slow and laborious, delaying the production and raising the production costs at the same time. The costs are also increased by the fact that the waste of coating agent is large in the cleaning phase. This is of significance, because the coating agent, for instance acrylate, has a high price. A further drawback of the prior art technique is that the cleaning work mostly is dirty work to be done by hand and, on top of it all, dangerous substances have to be handled.